Fluorocarbon ortho esters



Patented Sept. 23, 1952 .11.

UNITED STATES PATENT OFFICE e 7' l asim svkv 7 1 .FnUoRooArtBoN ORTHO ESTERS I I Torkil Helm, Minneapolis, 'Minn., ass'ignor to 1 Minnesota Mining & Manufacturing company, St. Paul, Minn a corporation. of'Delaware No Drawing-Application May 155i,

a i Serial No. 227,285 a This invention relates to my discoveryof a new and useful class of fluorocarbonestersf namely, the hydrocarbon orthoesters of the fluorocarbon mono-carboxylic acids; having the formula 3 where R: is a saturated fluorocarbon radical (consisting solely of carbon and fluorine), andR is a hydrocarbon radical.

Of particular interest are the hydrocarbon orthoesters of the perfluoroalkyl mono-carboxylic acids shown by the formula:

where R is a methyl (CH3), ethyl (C2H5), propyl (C3H1--) or butyl (C4H9) group, and n has an integer value of 1 to 11.

I have discovered that these new compounds can be made by a new process as indicated by the following reactions: /ONa R COOR RONB R,c-oR

(2) ONa OR RIC OR R2804 OR OR This process is of particular utility in the preparation of the subject compounds in view of the fact that to the best of my knowledge, there is no other known process by which they can be made. Attempts to make these compounds by methods ordinarily employed for making hydrocarbon orthoesters met with failure. As example, one reaction described by McElvain and Nelson (J. Am. Chem. Soc. 64, 1825 (1942) CHaONa C F100 CH8+QH3C O O CnHs C FJC O CHzCO O CzHt During the process of adding sodium methylate to the methyl perfiuoroacetate (and without the addition of the ethyl acetate) a solid material 1 Claim. (omen-#615 written thusly':

was obtained. No reaction'had been anticipated at this point. This solid material upon reaction with methyl sulfate was found to yield a product which upon analysis proved to be CF3C(OCH3):. The reactions which. actually occurred. may be ONa (JFsOOOCHa OHaONa CFBCZOCHI OCH:

ONa OCH: CFsC OCHa (CHahSOi CFsO-OCH:

OCH: OCH:

Consequent work with esters of other perfiuoro acids produced the corresponding higher homologues.

The simple orthoesters of any of the perfluoro acids, whether mono or dibasic, cyclic or noncyclic can be produced by the above described method. Likewise, the formation of polyorthoesters using the appropriate starting materials is feasible, said polyorthoesters being derived from either mono or dibasic perfiuoro acids and the appropriate dior polyhydric reactants.

I have already indicated that the preferred orthoesters contain lower alkyl groups such as methyl, ethyl, propyl or butyl. However, it should be obvious that orthoesters can be'prepared bythis process from the higher alkyl groups. Likewise, depending upon the choice of the ester of the perfluoro acid, the metal alkoxide and the alkylating agent, different alkyl groups may be had in the final product as exemplified by the formula:

i added, dropwise, 1 mol of a simple ester of a perfluoro acid and a hydrocarbon alcohol. After 30 minutes, one mol of the appropriate dialkylsulfate (alkylating agent) was added with continuous stirring. The mixture was stirred for 4' and the orthoester was isolated by fractionation of the ether solution.

The methyl orthoester of trifluoroacetic acid, CF3C(OCH3)3, boils at 106 C. at 740 mm. pressure, has a refractive index, 12, of 1.3380, and a freezing point of about minus 55 to 53 C. Elemental analysisin'dicated 34.6% carbon as compared with a theoretical percentage of 34.5, and 32.7% fluorine, with 32.7% as theoretical. Infrared analyses showed the absence of hydroxyl and carbonyl groups.

Higher molecular weight orthoesters were prepared including methyl orthoperfiuoropropionate, V

the a1ky1 phosphates and alkyl halides such as the bromides and iodides; ates other than sodium alcoholates can be used.

.. I-c1aim:' p

- 'Ihe new and useful compounds of the class Alkali-metal alcoholconsisting of the methyl, ethyl, propyl and butyl 4 orthoesters of perfluoro-alkyl mono-carboxylic acids, represented by the formula:

CnF2n+1C (OR) 3 where n has an integer value of 1 to 11 and R" is TORKIL HOLM.

REFERENCES CITED The following references are of record in the *s file of this patent:

UNITED STATES PATENTS Number Name Date 2,411,158- Hanford -2 Nov. 19, 1946 2,454,663 McGinty Nov. 23, 1948 2,567,011 Diesslin et al Sept. 4, 1951 OTHER REFERENCES 

